Today, cars are infinitely safer than 20, 30 or 40 years ago. This, of course, is due to significant structural changes that have been implemented over the years. Better materials, more intelligent builds, airbags, impact-absorbing crash zones and so on. All of these have made major differences in protecting passengers in the case of an accident. What arguably disrupted car safety even more, however, was the introduction of advanced driver assistance systems (ADAS).
What's today's state of the art?
ADAS are designed to step in when the driver won’t or can’t, oftentimes actively preventing accidents. There are many different systems in place and the list is steadily growing. We take a look at some of the more notable ones; the following list is meant to provide an overview, but names may vary between manufacturers.
Adaptive cruise control
Adaptive cruise control (ACC) is an effective tool to prevent rear-end collisions. In addition to classic cruise control, the system not only allows the driver to maintain a certain speed without having to use the pedal, it also monitors the distance to the vehicle ahead and intervenes accordingly. In order to do so, the system determines the position and speed of the car in front via laser, camera or radar and does the math, decelerating if necessary to adjust the distance and therefore avoiding a crash. That is why this system, as well as some of the following, can be considered an early stage of autonomous driving.
Blind spot monitor
The blind spot monitor reduces the risk of overlooking someone approaching the vehicle in the car’s blind spot, avoiding lateral collisions. This feature is especially useful when turning or changing lanes, as bicycles and motorcycles can be overlooked when relying solely on the rear-view mirrors. It monitors the neighbouring lane via cameras and sensors and gives a warning if something or someone is detected, which can be audible, visual or even tactile (like a vibrating steering wheel). The blind spot monitor is designed as a warning system and, as of now, is not meant to intervene on its own.
Collision avoidance systems
This system, that has become an important addition to car and passenger safety, was first developed for aircraft after several incidents called for action. If a forward collision is imminent, the collision avoidance system steps in. This can include an emergency brake function which, in a critical situation brings the car to an immediate halt, reacting faster than the driver could. Alternatively, the system can also steer clear of any objects ahead. These methods might not prevent a crash entirely, but they will at least reduce the impact and therefore severity of the accident.
Driver drowsiness detection
Inattention at the wheel can be fatal. Because of this, smartphones should never be used while driving and getting behind a steering wheel when tired is not a good idea. Reaction time before a crash is very limited as it is and averted or closed eyes can cost precious milliseconds. Driver drowsiness often stems from exhaustion, but it can also be an indicator of a health problems. Detecting a lack of attention is therefore a vital step in crash prevention. There are different ways in which the car can recognise a driver’s inability to drive and the goal is to identify signs as early as possible. Drowsiness can be identified by monitoring driving accuracy, such as the ability to stay in a lane. Noting small steering errors is another indicator for a driver’s state of wakefulness. The third approach is to observe the blinking speed and position of the head. There is, of course, a thin line between what can actually be considered drowsiness and when the driver is just behaving a little irregularly. In any case the warnings begin subtly, in order to not startle the driver and therefore cause a crash.
Lane centering and lane departure warning system
At a glance, the purpose of these two systems seems to be the same – to keep the vehicle in the lane. Taking a closer look however, there is a distinction in the execution of the functions. The lane departure warning system monitors the car’s position in the lane, usually by measuring the distance between the car and the lane markings. If the vehicle gets too close or crosses the markings without any indication of a turn or change of lanes the system alerts the driver visually, audibly or haptically. The driver then has to react accordingly. Lane centering, on the other hand, operates on a higher level of vehicle autonomy. It determines lane markings and the car’s position, just like the lane departure warning system, but instead of simply sending warning signals, the lane centering system assist in steering as well.
What's the technology behind this?
There are a multitude of technical features working together to support and enable advanced driver assistance systems. To explain all of them in detail would exceed the scope of this article. What we can do, however, is to take a look at some of the most important technologies behind ADAS.
Cameras play an increasingly important role in car safety. Modern vehicles are often equipped with multiple cameras that work together to create a picture of what is happening in and around the car.
Infrared technology distinguishes inanimate objects from beings that are alive, using a thermographic image to measure and analyse the temperature of an object thereby identifying it as human, animal or otherwise. This technology will gain importance in the field of autonomous driving.
Ultrasound is popular for measuring distances precisely. Today, it is often used by automatic parking systems, accurately mapping out a space in milliseconds. There are, however, many more mobility scenarios where this technology could be used in the future.
Just like infrared and ultrasound, Radar techniques don’t rely on a visual image and are therefore less influenced by poor visual conditions, such as fog or darkness. The radar emits electromagnetic waves and maps out street conditions.
One of the technologies that is becoming more and more popular in car manufacturing is LiDAR. The “light detection and ranging” emits light and measures the time that it takes to reach another object, thereby determining its position. It can be used to measure distances, as well as generating three-dimensional images of the surroundings.
Why can ADAS differ from country to country?
As ADAS perform highly important safety tasks, they are subject to strict regulations and national laws and practices. Accordingly, the extent, form and function of these systems can vary from country to country. Techniques that may be approved in some countries might not have passed the test in others or countries may prefer system A to system B.
How will these systems evolve?
When driver assistance systems first arrived they elevated cars on a level 1 on the autonomity scale, starting a development that is now steering directly towards autonomous driving of levels 3 and higher. You could argue, that driver assistance systems will be obsolete in the future – at least as individual systems – as there will no longer be a driver to assist. In their functionality, however, ADAS will become more important than ever before. Because they are, in fact, what will make autonomous driving possible, with the goal of making traffic even safer than it is today.